Vote as to who is the most powerful servant.
I'll admit that it's impossible to justify; a servant can beat another servant based on conditions, but putting all those factors into a battle is a logician's nightmare.

I'll go with Archer solely based upon the limitless possibilities of his Projection Magic. If one can't defeat one's enemy with what one has...then create it and make it possible. Even if it's "Faking", the end result is what matters. My vote goes to one who can make the impossible possible - Archer )

Gilgamesh on paper is the most powerful servant ever summoned, the problem is that he almost never get serious, thus crippling his own winning chances.

If we take that premise id say that most probably Berserker is the strongest. Saber can fight against him and win, but i seriously doubt even using Excaliblast that she can finish him before she dies.

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Heck against Gilgamesh Berserker lost 10 lives, got chained by Endiku, which its power increases the higher the divinity of its foe is, got babylowned by 22 noble phantasms at time (and since he couldnt move and was defenseless we could say that every phantasm killed him 1 time) and even after that he broke the frigging chains and charged Gil before being killed for the last time. Total deaths = 10 kills+22kills +1 last kill= 33 kills to truly finish Berserker, Holy Crap Batman, try to beat that monster Saber!!!!

In my opinion Caliburn was a plot weapon since it doesnt make much sense how the hell it killed him so many times with 1 blow

If we account Saber+plot hax> Berserker then id say that Archer is the most powerful one.

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Shirou managed to beat Alter Saber unleashing Kanshou and Byakuya overdrive so Archer could do it too since hes faster, stronger and more skilled than Shirou, even if he uses Garm. Saber has pride so its unlikely that she uses Excaliblast against a meleeing Archer (Kinda a chavalry code: Her oponent is not as good as her in close combat but even having that handicap hes fighting her. Atacking him from range in that case she probably would consider it cowardly and dishonorable) unless he start spamming atacks from range.

Plus Saber rarely uses her Noble Phantasm unless the situation is critical for her such as being overwhelmed, or if her honor requires it

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Against Kojirou in Fate she was about to use it when Shirou appeared to respond Assasin courtesy

But in any case most cases are situational. since some Servants are like scissor paper and rock. But id say that those 3 are the strongest in general levels.

Weapon level doesnt mean much if his wielder dont use it and Gilgamesh is a good example since he could have finiched the Grial war in the first night if he wanted to

Edit: Even the strongest servant can be defeated if he lower his/her guard

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Saber was defeated by Bazette a human magus in hollow ataraxia by countering Excaliblast

inferno_flamex wrote:
And lets not forget about Avalon now wont we?
Remember that you cant do anything if you're dead after a uber strong attack...

moreso if it kills you

anyway, I approve of Rai's and wyldfire's posts

ps... hey!, 400 lol

"We want a game that's going to chop us the second we screw around, or just flatten us at its whim... until we finally beat it. They demand more of us, and we rise to the occasion because we're that good. And that feels good. And that's why we game."
Rus McLaughlin, IGN

3. Assassin would get pwned because he can't leave the gate. Kaladbolg II ftw. *boom* HEAD SHOT! XD
4. Rider is just plain weak because she is controlled by Shinji and

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Sakura doesn't like fighting.

5. Berserker wouldn't be able to win if Archer used UBW from the start.
6. Lancer is probably the only Servant with a good chance of victory against Archer because of his speed. (he would never give Archer the chance to pull off UBW)
7. Caster just epically fails against Archer

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(as proven by their first battle where Archer purposely didn't kill Caster).

Edit: . Hassan is just plain pathetic, the only good move he has is Delusional Heartbeat which needs a good opening to pull off. 1 v 1 he would lose within seconds.

So the only Servants with a chance against Archer (if hes serious) are:
Saber, Lancer, and Berserker (cause hes gots likez 10000000 lives).
Debatable yes, but this is how I see it.

No one is going to win 100% of the time. Especially if we're talking actual combat where tactics, internal conflict and terrain can all influence the outcome.

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Gil, pretty safe bet. He lost against what was essentially a weaker, less experienced version of Archer, and died in the other two arcs by playing around with foes he should have finished off.
Saber has the advantage not just because of her overwhelming melee power, but also because he's prone to hesitation and she is not (Night of Fate). It was pretty obvious in HF that she didn't want to kill Shirou, we can safely assume that she wasn't fighting with her full strength in that duel.
Assassin and Rider would be at a heavy disadvantage, but a well executed surprise attack or a fatal wound to the master could win it for them.
Berserker would win, 9/10. Gil won against Berserker because of his chain, which was barely enough to turn the fight in his favor.
Lancer is another one that matches up very well, as UBW shows.
Caster would need an amazing plan. She'd have to shoot the moon and break his contract, then keep him under control after the fact.
Hassan is pretty weak like you said. He'd need a miracle (although he did pull one off by beating Saber).